[cnst]

It depends.™

I've had a static IPv4 subnet allocation from AT&T on AT&T U-verse, and tried using it on a couple of consumer routers for the local network. Well, guess what — all these devices from major brands that are called "routers" don't actually route between the interfaces, after all — all they did was NAT between my public IPv4 allocation and the main IPv4 address assigned by DHCP. And disabling the NAT simply disconnected the networks — instead of rounting one interface to the other. I actually opened up a support ticket with ZyXEL, which got escalated to their engineering managers, and they did confirm my finding that their routers had a bug in sysctl settings that stops them from routing the interfaces (e.g., sysctl net.ipv4.ip_forward not set to 1).

Anyhow, back to T-Mobile US IPv6 on a hotspot — when I originally tried ssh'ing back to my own box via the public IPv6, things didn't work, either; but I then found out that it was some sort of a local policy on the local machine, because another laptop without a firewall was able to receive connections on IPv6 from the internet without any issues.

[anticensor]

Were they all just selling NAT-ing bridges instead of routers? This is a serious fraud.